Obviously the GOP would need to adapt for IL to become a Tossup, but they pretty much have to do that anyway under any scenario in which they want to remain relevant. Also, this is 2044, A LOT can happen, and it’s foolish to assume that the Electoral Map will be the same for all eternity. All that said, Illinois should still be a difficult state for the GOP to win. We all know as of now that Illinois is quite competitive on the state level.
https://uselectionatlas.org/RESULTS/state.php?fips=17&year=2016&f=1&off=10Problem for the GOP there is that over the tenure of a Republicans time in office is that it is hard to meet the contradictory demands of both the collars and downstate. Also DuPage and Lake County seem to be moving to the Democratic party very quickly.
It is a tough nut to crack for the GOP even if they can be competitive there.
But like you said a lot can change over time. In 1992 Bush 1 carried Dupage County easily and Will was the only Collar County to vote Clinton while Southern Illinois was heavily for Clinton.
In 2016 Clinton carried all the Collar Counties except McHenry and the GOP could not even carry DuPage in the Senatorial contest. Hillary was annihilated in Southern Illinois.
Anyway here is my wild guess for 2044